Fire ignites at Recology’s Sonoma Marin Landfill amid California heat wave

A significant fire at a Recology-owned landfill in Novato, California, had firefighters working against an “oppressive heatwave” to control the blaze.

The fire started at the Sonoma Marin Landfill at about 10 p.m. Sept. 6, reports CBS News. At the time of the fire, a heat wave had driven temperatures in the area into triple digits for much of the day.

According to Novato Fire Protection District Battalion Chief Jeff Whittet, the fire appears to be accidental and not suspicious in nature. He told CBS News the Novato Fire District sent crews to battle the flames and were joined by units from Marin County Fire, Central Marin Fire and North Bay Fire.

Firefighters say the blaze was fueled by construction materials such as drywall and lumber; however, a spokesperson with the Gypsum Association, Silver Spring, Maryland, says this is likely not the case.

In an email to Waste Today, the Gypsum Association notes that gypsum drywall is “inherently non-combustible,” which is “precisely why drywall is used in 99 percent of structures today.”

“When a gypsum panel is exposed to high temperatures, it does not ignite. Instead, the surface releases steam as the chemically combined water in the core is released. Heat transmission is obstructed until this slow process, known as calcination, is complete,” the spokesperson says. “During a fire, wood or steel structural members covered with gypsum panels are protected and the fire is contained because the temperature behind the panel is significantly lower than the temperature at which steel loses strength or wood ignites.”

According to the Gypsum Association, this fire-resistant nature can be credited to the chemical composition of gypsum. Gypsum, or calcium sulfate dihydrate, is an inert compound containing 21 percent by weight chemically combined water. Both natural gypsum and synthetic gypsum share this inherent characteristic, which is leveraged to provide buildings, including homes, with passive fire resistance.

Waste Today has reached out to the Novato Fire District for more information on what may have sparked the fire.

Photos shared by the Novato Fire District on Twitter show flames burning amid the piles of debris: 

Novato Fire District personnel with assistance from Marin County Fire, Central Marin Fire and North Bay Fire controlled a large debris fire at the Sonoma Marin Landfill. Smoke is visible from Highways 101 and 37. No structures were damaged and no injuries reported. ?????? pic.twitter.com/jAZgUmLEwU

— Novato Fire District (@NovatoFireDist) September 7, 2022

As reported by CBS News, smoke and flames were visible from Highways 101 and 37. No structures were damaged, and no injuries were reported.

The “deep-seated” nature of the fire necessitated a “lot of work to tackle,” according to firefighters. CBS News last reported Sept. 7 that large water tenders were being employed to put the fire out. Bulldozers were also used to “push out” extinguished matter to be cooled and covered.

Editor's Note: This article has been updated to include statements from the Gypsum Association on the characteristics of gypsum drywall.